In recent literature (Chasen, 1935; Peters, 1940; Delacour, 1947; Smythies, 1957) two races of Bubo sumatranus are recognized : B. s. sumatranus (Raffles) from Sumatra, Bangka, and the Malay Peninsula, and B. s. strepitans (Temminck) from Java and Borneo.From the zoogeographical point of view a distribution as indicated above is unexpected, as generally speaking the faunas of Sumatra and Borneo are very similar, while that of Java is more distinct from either. The suspicion that the current classification might be erroneous induced me to examine the material of the species available in the Rijksmuseum van Natuurlijke Historie, with a result that is presented here. Plumage characters and measurements given are of adult specimens only; juveniles, which can easily be recognized by their whitish plumage, have not been considered.Bubo sumatranus strepitans (Temminck) Strix strepitans Temminck, 1823, Recueil d'Ois. 2, livr. 30, pi. 174 — Batavia.Strix orientalis Horsfield, 1821, Trans. Linn. Soc. Lond. 13: 140 — Java. Preoccupied.Characters. Size large; cross-bars on lower part of under surface broad and far apart.Measurements of wing, &lt;5 : 370. 379, 381, 384, 385, 388, 388, 388, 392, 392, 395 mm. ?: 376, 386, 395, 397, 405, 408, 410 mm. sex?: 417 mm.Distribution. Java and Bali.Remarks. The outstanding character of this race, large size, was correctly observed by Schlegel (1863) and several subsequent authors. Stuart Baker (1927: 419) mistakenly stated that the race from Java is smaller than that of Sumatra and Malaya.Amongst the specimens studied is the holotype of Strix strepitans Tem-